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Study of Hydrodynamics and Overall Gas Hold Up Validation in Bubble Column by Computational Fluid Dynamics
Get PDFThe study of overall gas hold up has been carried out experimentally with the bed expansion. The superficial gas velocities used for the experiments are 6.369 m/s and 10.616 m/s. The experiment is carried out in a bubble column with inside diameters of 7 cm and a height of 100 cm. Gas from the gas cylinder is supplied through a distributor consisting of a perforated plate and glass beads. The perforated plate has a hole diameter of 1 mm and 0.5 mm. Computational Fluid Dynamic (CFD) using a Eulerian coupled with Population Balance model is developed to predict overall gas hold up and bubble size distribution. The effect of superficial gas velocity, perforated plate diameter, gas properties, and initial liquid level on gas hold up were studied. The use of population balance can significantly improve the overall gas hold-up results compared to constant bubble diameter. It is found that several operating conditions affect the whole gas hold up, namely initial liquid level, superficial gas velocity, and differences in gas properties. While the influence of the difference in perforated plate diameter to overall gas holds up, results are small compared to other operating conditions
The Performance of Ramsey Test, White Test and Terasvirta Test in Detecting Nonlinearity
Get PDFThe objective of this research is to compare Ramsey test, White test and Terasvirta test in the identification of nonlinearity. Ramsey test is a test based on the regression specification error test. While White test and Terasvirta test are based on neural network models. The difference between White test and Terasvirta test is in determining its weight, White test based on random sampling, while Terasvirta test based on Taylor expansion. Simulation studies are carried out with various scenarios in each test by generating linear models, linear models with outliers and nonlinear models. The results of the simulation study showed that Terasvirta test had better power than Ramsey test and White test in detecting nonlinearity. Terasvirta test is also more sensitive to the presence of outliers in linear models
Faktor-Faktor yang Mempengaruhi Produktivitas Tenaga Kerja berdasarkan Sistem Pemberian Upah Borongan di Kabupaten Sampang (Studi Kasus Pembangunan ICU RSUD Kabupaten Sampang)
Get PDFPerkembangan teknologi sangat berpengaruh terhadap kemajuan di berbagai aspek khususnya di bidang konstruksi. Persaingan bisnis yang semakin ketat antar perusahaan jasa pelaksanaan konstruksi (kontraktor) memicu para pelaku usaha untuk berlomba-lomba memberikan pelayanan atas kepuasan pelanggan. Oleh sebab itu sangat penting bagi perusahaan untuk memperhatikan produktivitas tenaga kerjanya. Dengan upah yang sesuai akan memberikan kepuasan dan semangat kerja pekerja yang dapat meningkatkan produktivitasnya sehingga perusahaan pun mendapatkan hasil yang optimal. Berdasarkan latar belakang yang telah diuraikan, akan dilakukan penelitian tentang faktor-faktor yang mempengaruhi produktivitas tenaga kerja konstruksi borongan. Metode penelitian yang digunakan dalam penelitian kali ini adalah metode analisa statistik deskriptif yaitu dengan mengumpulkan data primer dan data sekunder. Data primer merupakan data yang diperoleh langsung dari sumber pertama seperti wawancara dan pengisisan kuesioner, sedangkan data sekunder merupakan jenis data yang diperoleh dari sumber kedua seperti uji literature atau tinjauan pustaka. Pengujian ini menggunakan pengujian Kruskall Wallis. Dari data diketahui bahwa pada empat variabel masing-masing dengan sampel berjumlah 32 memiliki mean ranks berturut-turut yaitu 27,25 pada variabel X1 (kecepatan kerja), 84,81 pada variabel X2 (kerjasama), 84,94 pada variabel X3 (semangat kerja) dan 61,00 pada variabel X4 (loyalitas kerja)
Penerapan Manajemen Fasilitas dan Smart Mobility di PT. Kereta Api Indonesia (Persero)
Get PDFPenelitian ini bertujuan untuk mengetahui penerapan manajemen fasilitas dan smart mobility di PT. Kereta Api Indonesia (Persero) dengan eksplorasi kejadian atau fenomena yang dapat dijadikan pelajaran berharga bagi pengembangan teori dan kondisi eksisting penerapan tersebut. Penerapan manajemen fasilitas diukur dengan peningkatan kualitas layanan dan peningkatan inovasi layanan. Indikator pengukuran untuk penerapan smart mobility yakni penambahan kapasitas layanan, pengaplikasikan teknologi, dan peningkatan fasilitas operasional. Dari penelitian ini diketahui pengembangan fasilitas-fasilitas layanan terbaru yang diberikan PT. Kereta Api Indonesia sudah menerapkan konsep manajemen fasilitas dan smart mobility sehingga memberikan pelayanan yang memudahkan pengguna layanan jasa transportasi kereta
Board of Editor
Get PDFBoard of Editor PATRON: Dean - Faculty of Civil, Environmental, Earth Sciences - ITS.Head Training Center Management & Functional Position - Ministry of PWPH. RESPONSIBLE : Head of Department – Civil Engineering Department - ITSBOARD OF EDITOR Chief Editor : Hitapriya Suprayitno ITS, Indonesia h-index (GS = 8)Editor : Ria Asih Ariyani Soemitro ITS, Indonesia h-index (GS = 9) Data Iranata ITS, Indonesia h-index (GS = 3) Alex Abdi Chalik PUPR, Indonesia h-index (GS = ) Danang Parikesit UNIID, Indonesia h-index (GS = 7) Maimunah Sapri UTM, Malaysia h-index (GS = 14) Address : Editor JIFAM – Room J - 201 Departement of Civil Engineering Institut Teknologi Sepuluh Nopember ITS Campus, Sukolilo, Surabaya 60111 Email: [email protected] Website: https://iptek.its.ac.id/index.php/jifamReviewer for this EditionRia Asih Aryani Soemitro, Insitute of Technology Sepuluh Nopember (ITS), Surabaya, Indonesia.Data Iranata, Institute of Technology Sepuluh Nopember (ITS), Surabaya, Indonesia.Caroline Sutandi, Universitas Parahyangan, Bandung, Indonesia.Eko Budi Santosa, Instiute of Technology Sepuluh Nopember (ITS), Surabaya, Indonesia.Akhmad Wicaksono, University of Brawijaya, Malang, Indonesia.Hitapriya Suprayitno, Insitute of Technology Sepuluh Nopember (ITS), Surabaya, Indonesia
Preliminary Reflection on Basic Problematics of National Public Infrastructure Financing in Indonesia
Get PDFFurnishing adequate national public infrastructure is an obligation for the government. Financing the infrastructure is not an easy problem. The main problem are that the NREB cannot finance the investment cost and the NREB capacity is not enough to finance he whole infrastructure needed. If in general the public infrastructure is merely a cost, there are certain infrastructure which can generate revenue. Meanwhile the GDP is far higher then the NREB. So, thinking involving private fund in public infrastructure financing is logical. Thus public infrastructure financing should be a mixture of public and private fund. The activity involving the Private Sector must be in an Attractive Comercial Activity. Thus preferably for revenue generator infrastructure. Revenue can be generated in various form. The basic idea of solutions can be grouped into fully financed by public budget, by a mixture of public private fund, and by fully private financed. Each group has its owned characterisitcs and derivative solution.
Failure Analysis of Superheater Tubes Made from Material T91 in the Boiler of a 600 MW Power Plant
Get PDFThis paper highlights a study for the failure investigation of superheater tubes made of the material T-91 of a boiler in the coal-fired power plant. Two tubes are subjected to different types of failure. Visual examination, dimensional measurement, and chemical analysis are conducted as part of the study. Apart from these, the hardness test and microstructural analysis are also conducted to ascertain the possible cause of failure. The superheater tube material cracking, cavity until broken failure that occurred on the first tube was resulted in thick lip rupture and the second tube resulted in thin lip fish mouth rupture. Creep deformation, localized rapid overheating, surface tube erosion, and fly ash of coal corrosion are the main cause of tube failure. It can be avoided by regularly and according to standards cleaning the scale or deposit on the surface of the tube
Analysis of Pipe Lay Barge Hafar Neptune Capability in Pipelaying Operation at Offshore North West Java Oil and Gas Field
Get PDFWhen pipelaying activity is carried out, the most influential factor is the significant wave height. In this final project, the maximum significant wave height allowed for the PLB during the pipelaying process was analyzed with the variation of pipe diameters, which are 8 inches, 10 inches, and 12 inches; variations in the direction of coming waves namely 0o, 45o, 90o, 135o, and 180o; and stinger angle variations. First, static analysis was performed using OFFPIPE software Then, Pipe Lay Barge (PLB) Hafar Neptune modelled with MOSES software and validated with ABS MODU codes. The output was RAO from the Hafar Neptune PLB. Next, dynamic analysis was performed with OFFPIPE software, where the input is static analysis, RAO of Pipe Lay Barge Hafar Neptune, and JONSWAP wave spectrum formulation. The result of the analysis was the significant wave height that could hit the PLB when pipelaying is 3 meters for all pipe diameter variations. For variations in the direction of the wave data, the maximum Hs were 3 meters for 0 ° and 180 °, 2.5 meters for 45 °, 1.5 meters for 90 ° and 135 °
Perbandingan Citra Hasil Rekonstruksi Metode Newton-Raphson dan Landweber pada Electrical Capacitance Tomography: Analisis Resolusi dan Akurasi
Get PDFPenelitian untuk membuat desain Electrical Capacitance Tomography dilakukan menggunakan metode numerik Finite Difference Method (FDM) untuk forward problem dan ditentukan tingkat akurasinya terhadap metode analitik. Solusi berbasis FDM yang diperoleh, digunakan dalam proses rekonstruksi menggunakan metode Landweber dan Newton-Raphson. Perbandingan citra hasil rekonstruksi dari kedua metode dianalisis berdasarkan resolusi dan akurasi citra yang dihasilkan. Hasil penelitian ini menunjukkan bahwa akurasi Finite Difference Method dengan melakukan pemotongan garis pada objek domain, didapatkan 90,57% pada garis horizontal dan 87,43% pada garis vertikal. Adapun hasil untuk rekonstruksi didapatkan akurasi proses rekonstruksi 98% untuk Newton-Raphson dan 88% untuk Landweber. Resolusi citra yang direkonstruksi dengan menggunakan Newton-Raphson mampu membedakan 2 benda dengan jarak pisah minimal 3 cm, sedangkan Landweber mampu membedakan 2 benda dengan jarak pisah minimal 8 cm
Karakterisasi Stabilitas Termal Kaolin Tatakan Kalimantan Selatan
Get PDFKarakterisasi stabilitas termal kaolin Tatakan Kalimatan Selatan telah dilakukan. Penelitian ini bertujuan untuk mempelajari pengaruh termal yang diberikan kepada lempung kaolin untuk penggunaannya sebagai bahan dasar geopolimer. Lempung kaolin yang telah dipreparasi, dikarakterisasi dengan FTIR, DSC-TGA, dan XRD. Hasil analisis DSC-TGA menunjukkan peristiwa predehidroksilasi terjadi pada suhu 50-120°C, dehidroksilasi terjadi rentang 430 - 650°C dan keadaan paling stabil teramati pada suhu 700°-900°C. Suhu kalsinasi pada lempung kaolin diberikan pada suhu 650°C, 750°C, dan 850°C dengan waktu tahan 1, 3, dan 5 jam, lempung kalsinasi selanjutnya dikarakterisasi FTIR dan XRD. Hasil FTIR menunjukkan untuk seluruh perlakukan termal telah terbentuk metakaolin yang ditandai hilangnya puncak karakteristik kaolin bilangan gelombang 3600 cm-1 dan 1600 cm-1. Perlakuan termaldengan suhu 750 ̊ C dengan waktu tahan 3 jam yang menunjukkan bahwa fasa amorf paling banyak terbentuk yang ditandai dengan terlihatnya penurunan prosentase transmintansi semakin tinggi. Hasil analisis qualitatif dari pola XRD hanya menunjukkan fasa quartz sedangkan fasa kaolinit tidak ditemukan. Hasil ini menunjukkan koherensi dengan hasil FTIR. Perlakuan termal terhadap kaolin tatakan untuk menghasilkan metakaolin reaktif sebagai aplikasi geopolimer dikalsinasi dengan suhu 750°C selama 3 jam